06.03.14 9:45 AM ET

Barring a political earthquake that would shock prognosticators from Orange City to Ottumwa, the Republican nominee for U.S. Senate in Iowa will likely be State Sen. Joni Ernst.

Ernst, a first-term senator from the southwest Iowa town of Red Oak, is the overwhelming favorite to face Democrat Bruce Braley in the fall after being an underdog for much of the campaign. She used a series of highly successful television ads to paint herself a Palinesque female conservative, complete with glasses and handgun, and make herself the front-runner. The question for Ernst is whether the tactics she used to come from behind in the primary against businessman Mark Jacobs may backfire in the general election.

The Republican field in the Senate primary was never considered to be the state GOP’s A-Team as two incumbent Republicans in Congress, Tom Latham and Steve King, both bowed out, as did statewide officeholders like Lt. Gov. Kim Reynolds and Agriculture Secretary Bill Northey. Instead, the favorite for much of the primary was Jacobs, a former CEO of Reliant Energy who freely spent his personal wealth on his campaign. But Jacobs was always viewed skeptically both by the Republican base as well by D.C. insiders and had difficulty breaking away from the field despite spending heavily on television and direct mail.

The key moment was when Ernst released her first television ad in late March, which focused on her childhood chore of castrating hogs. That ad, combined with the release of video of Braley at a Texas fundraiser seemingly mocking Iowa farmers, immediately boosted Ernst into first place in polls and she hasn’t budged since.

Ernst has also been aided by being a unique compromise candidate. In a year where establishment vs. Tea Party conflict continued to rage within the GOP, she may be the only candidate endorsed by the strange quartet of Mitt Romney, the Chamber of Commerce, Sarah Palin, and the Senate Conservatives Fund. The result made her one of the candidates who can appease both elements of the party, but she’s done so without really winning over either fervent conservatives or many entrenched establishment Republicans.

Yet, despite being a compromise candidate, it’s possible Ernst may have deeply hurt her chances to win the open Senate seat in this swing state before the general election even starts thanks to her attempts to prop up her standing with conservatives. The state senator, who repeatedly described herself on the trail as a “mother, soldier, and a conservative,” zigged to the right in order to appeal to primary voters, pledging to abolish the Department of Education and the Environmental Protection Agency. While Ernst received attention for calling the shootings in Santa Barbara, California, an “unfortunate accident” in a recent debate, she may have done more damage by opposing the Farm Bill and attacking the Clean Water Act in an agricultural state. Further, Ernst has shown herself to be prone to gaffes, including insisting to the Des Moines Registerthat Saddam Hussein actually possessed WMDs prior to the Iraq War.

Ernst though isn’t quite a shoo-in for the primary and there is some limited potential for surprise. Turnout is expected to be relatively low and Ernst isn’t the candidate with the best ground game—that’s Jacobs, whose campaign has knocked on 41,000 doors and contacted 150,000 voters in total—and she isn’t the one with a strong core of evangelical grassroots supporters either (that’s social conservative Sam Clovis, who has key endorsements from Rick Santorum and GOP kingmaker Bob VanderPlaats). Even if Ernst comes out ahead on the day of the primary, it doesn’t mean she’s won.

Iowa’s quirky election law requires a candidate to receive at least 35 percent of the vote in a primary to win a nomination. If that threshold isn’t achieved, party activists at a state convention will select a nominee and don’t need to limit themselves to candidates on the ballot. In a field that also includes former U.S. Attorney Matt Whitaker as well as a car salesman named Steve Schaben, it’s possible, though not terribly likely, that Ernst could be pushed below that 35 percent threshold. And, even if the race does get decided at convention, there’s a general consensus that Ernst will be the nominee. As one connected Iowa GOP operative points out, longtime incumbent Governor Terry Branstad, who is believed to be quietly backing Ernst, undertook an organized effort in this year to pack the state convention on his behalf. This wasn’t to aid Ernst but rather to ensure that he could take control of the state GOP from libertarians and avoid any challenge to the re-nomination of Lt. Gov. Kim Reynolds. The result is that the state convention may be one of the few times in which the Tea Party and social conservatives may have more sway in a primary than a convention.

Regardless of what path Ernst takes to get the nomination, it seems likely that she’ll be the GOP standard bearer. The question is whether, after a primary focused on castrating hogs and shooting Obamacare, Ernst will be able to successfully pivot to appeal to the general electorate in a state as purple as Iowa.